9:35 AM

If you like to experience a wide variety of weather and all seasons all at once, this week is for you.  If you like thunderstorms and heavy rain, this week is for you!  If you like cold air and snow, yes this week is for you!  If you like your weather like recent politics and enjoy REAL CHANGE, this week is for you!

This morning, the water vapor satellite image shows an exiting Polar trough and the approach of an impressive cold front driving through the center of the nation.  The cold front is currently pulling a large amount of warm, moist air northward into the Great Lakes and starting to produce a line of heavy rain with embedded thunderstorms.  Behind this cold front is the start of some drastic changes back to cold and this time very active winter weather.

Through this weekend, high pressure will be in control with pleasant, dry conditions and almost late February like conditions with temperatures averaging slightly above normal in the 40′s.  As the high pressure slides to the east of the northern Mid Atlantic tonight, a southwesterly wind will develop, bring a surge of mild air into the Philadelphia and New York City metropolitan area.  However, these pleasant conditions will not last long.

The strong cold front over the Plains this morning will sweep eastward towards the coast by Monday morning.  This cold front will create some chaos with the usual temperature patterns in this region.  The warmest temperatures will be in the morning ahead of the cold front as temperatures push into the lower to mid 50′s.  With the warm temperatures and high dew points, the atmosphere will become very unstable, producing some embedded thunderstorms and heavy downpours.  The Monday morning rush hour is not going to be pretty with the potential for heavy rain to produce reduce visibility, flash flooding, and a high potential for hydroplaning.  The thunderstorms associated with this cold front will be capable of downburst winds as the significantly colder temperatures at 600 and 700 MB (mid levels of the atmosphere) rush down towards the surface to fill the void left by the rapidly rising air ahead of the cold front.  This is typically an issue in the Spring and Summer, but can happen in these cases of rapidly changing air masses.  So strong wind gusts will also be an issue to keep an eye on for Monday morning.  As the cold front exits after the early afternoon, temperatures will start to rapidly fall through the 40′s and into the 30′s by the evening.  Those enjoying the warm conditions in the morning will be shocked by the drastically cold conditions as they leave work in the late afternoon, so be prepared.

As the cold front exits, a new upper level pattern will be established with the Polar and Sub Tropical jet streams.  A deep trough will become well established over the eastern two-thirds of the nation, leading to a series of weak cold fronts to move through the region Tuesday through Thursday.  Along with the return of drastically colder temperatures with highs in the 20′s and 30′s much like the start of January, each cold front will bring the threat of scattered snow showers and even a brief burst of heavy snowfall with isolated snow showers.  I’m introducing the threat of a brief snow burst as this introduction of Arctic air interacting with a what has become a relatively warm boundary layer may produce mesoscale areas of instability, especially along the coast.  Just something to keep an eye on as the week progresses.

Towards the end of the week, the pattern becomes increasingly interesting.  A favorable MJO phase in stage 7, will support an active Sub Tropical jet stream leading to a strong disturbance interacting with the stationary Arctic cold front stretching from the southern Plains to the southern Mid Atlantic coast.  With the Gulf of Mexico open for business to supply plenty of moisture and a cold air source already established, there is significant support for an accumulating snowfall (perhaps significant snowfall) for the northern Mid Atlantic Friday evening through Saturday.  The details of this storm are still undetermined, but there are a lot of indications pointing to a low pressure system moving from the Southern Plains towards the Mid Atlantic coast and making a turn towards the bench mark of 40N/70W in this time period.  Considering that the Arctic air mass will be well supported by high pressure over the Great Lakes and plenty of ample moisture will be available, a significant threat is present for this time period.

So there we have it!  A week that really brings just about every weather condition you can experience for this time of year and the potential for much more winter weather appears to be growing through the rest of the month.